iSync 6600 fm 5.27.0 buggy

Hi guys,
do you also experience problems with Apple's iSync (OS X.3.7) and the Nokia
6600 running firmware 5.27.0?

I cannot get to sync my Mac with my N6600 to save my life. Complete
reset/reinstall of both cell phone and Mac didn't solve my problem.

I think it's a firmware bug, those of you that have version 4.09.1 seem to
have no problems.

Any ideas?

Can I downgrade my Firmware somewhere?

Thanks in advance,
Joe